const shape = { radius: 10, pada() { return this.radius * 2; }, xiada: () => { return this.radius * Math.PI * 2 } } console.log(shape.pada()); //20 console.log(shape.xiada()); //NAN 求大佬解答,为啥第二个输出是NAN啊,我作用域这块儿经常整不明白😫